Scrutinizing velocity and pressure coupling conditions for LES with downstream RANS calculations

Dominic von Terzi*, Wolfgang Rodi, Jochen Fröhlich

*Corresponding author for this work

Research output: Chapter in Book/Conference proceedings/Edited volumeConference contributionScientificpeer-review

5 Citations (Scopus)


A RANS calculation is connected to an upstream LES via explicit coupling conditions at a pre-defined interface. The role of the interface is to allow for mean flow information to propagate upstream and for fluctuations to leave the LES domain without reflections. To this end, the mean velocity is directly coupled across the domain boundaries whereas the fluctuations at the downstream end of the LES zone are treated using either the so-called enrichment strategy (Quéméré & Sagaut, 2002) or a parameter-free generalization of this method based on a convective condition (von Terzi, Fröhlich & Mary, 2006). For incompressible flows, both techniques require a complementary coupling condition for the pressure or an equivalent variable enforcing continuity. Two distinct techniques are investigated: (i) The instantaneous pressure is computed in a coupled fashion for the union of the LES and RANS domains and (ii) the pressure is completely decoupled and mass conservation across the interface is ensured by an adjustment of the velocities on both sides. The performance of the different methods is scrutinized for turbulent channel flow and the flow over periodic hills. It was found that the convective condition with decoupled pressure fields and an explicit mass flux correction was the most robust technique delivering results of equal or increased quality in comparison to other combinations considered.

Original languageEnglish
Title of host publicationAdvances in Hybrid RANS-LES Modelling
Subtitle of host publicationPapers contributed to the 2007 Symposium of Hybrid RANS-LES Methods, Corfu, Greece, 17-18 June 2007
EditorsShia-Hui Peng, Werner Haase
Number of pages10
Publication statusPublished - 2008
Externally publishedYes

Publication series

NameNotes on Numerical Fluid Mechanics and Multidisciplinary Design
ISSN (Print)1612-2909


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